[Info-vax] Why does this DIFF command fail, then run fine the 2nd time around?

[alanfe...@gmail.com]

On Monday, December 12, 2022 at 7:26:54 PM UTC-5, Dave Froble wrote:
> On 12/12/2022 5:24 PM, Stephen Hoffman wrote: 
> > On 2022-12-12 21:18:18 +0000, Dave Froble said: 
> > 
> >> On 12/12/2022 1:27 PM, Stephen Hoffman wrote: 
> >>> On 2022-12-12 06:45:44 +0000, alanfe... at gmail.com said: 
> >>> 
> >>>> $ DIFP SCRFELD:[.A.TO_V530]CLEAR_NBACK_LNMS.COM;1 [.B.*] 
> >>>> ... 
> >>>> $ SHOW LOG/FUL SCRFELD 
> >>>> "SCRFELD" [super] = "DSA2:[USR_SCRATCH.FELDMAN.]" [concealed,terminal] 
> >>>> (LNM$PROCESS_TABLE) 
> >>>> $ 
> >>> 
> >>> AFAIK, usual preferred command syntax with a concealed rooted logical name 
> >>> would be thus: 
> >>> 
> >>> DIFP SCRFELD:[A.TO_V530]CLEAR_NBACK_LNMS.COM;1 [B.*] 
> >>> 
> >>> Trailing dot (from the logical name, correctly) and leading dot (from the 
> >>> appended directory) passes along some variation of [TOS..A] and [TOS..B]. 
> >>> 
> >>> Looks likeasdf a dusty corner within the name and default name and related-spec 
> >>> parsing, among other dusty corners within filespec parsing. 
> >>> 
> >>> Shouldn't blow up, but arguably also probably shouldn't work. 
> >>> 
> >> 
> >> Some people are way too fond of rooted logical names ... 
> > 
> > There are some people too fond of logical names, too.
> Ayep ...
> > Though this case looks more like filename parsing gone awry.
> It's the other side of lots of flexibility, many options,some might claim too 
> many options.
> > Wouldn't be the first time there was a bug in filename parsing either, as 
> > somebody else (A.M.) once remarked. While debugging a parsing-related error.
> The rooted logical stuff is interesting, but, sometimes just because one can do 
> something, doesn't then mean that they should do it. 
> 
> The early developers wanted multiple OS roots. Ok, maybe that might be Ok. But 
> then others took the concept, and used it where it just wasn't needed. They did 
> it because they could. Reminds me of "the road to hell is paved with good 
> intentions" and other such.

I find the rooted directory bit very useful. In this case, I can maintain a parallel world on the scratch disk on EISNER. The top directories aren't the same, but with the rooted directory, I can make my own directory tree the same. 

I can have

DISK_USER:[DECUSERVE_USER.FELDMAN]
  SCRFELD:[DECUSERVE_USER.FELDMAN]

Then I can create a parallel directory structure on the scratch disk, move less important old versions of files and other less important files to SCRFELD:, where I am not limited by a disk quota. 

I can use commands like $ BACK/VERI/DELE files SCRFELD:  !!!  and the files go over without having to specify the scratch disk version of the directory I happen to be in!



> > OpenVMS filename syntax is... baroque.
> Don't make me look up that word ... 
> 
> :-) 
> 
> I have no problem with the basic filespec stuff. I actually prefer the 
> "[a.b.c]" directory specification over "/A/B/C", but I do understand the latter 
> might be easier to parse. Don't know, never used it much. Don't like it.
> > More baroque in recent years, in service to continued app compatibility.
> If apps don't get "tricky" then perhaps compatibility might be easier.
> > DIDing, FIDing, ^U, mount points, what's implemented in the CRTL and what's in 
> > the XQP, etc.
> Ok, opinion time. The CRTL should deal with C stuff. VMS stuff has no place in 
> the CRTL. Just my opinion. Originally VMS stuff had System Services, LIB$, 
> etc. Then someone got lazy.
> -- 
> David Froble Tel: 724-529-0450 
> Dave Froble Enterprises, Inc. E-Mail: da... at tsoft-inc.com 
> DFE Ultralights, Inc. 
> 170 Grimplin Road 
> Vanderbilt, PA 15486